scholarly journals Foam Structure Preservation during Microwave-Assisted Vacuum Drying: Significance of Interfacial and Dielectric Properties of the Bulk Phase of Foams from Polysorbate 80–Maltodextrin Dispersions

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1163
Author(s):  
Peter Kubbutat ◽  
Ulrich Kulozik ◽  
Jannika Dombrowski
Keyword(s):  
Dielectric Properties ◽  
Surface Film ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Polysorbate 80 ◽  
Drying Time ◽  
Foam Structure ◽  
Structure Preservation ◽  
Microwave Assisted ◽  
Working Frequency

This study aimed at examining the cause of differences in the structure preservation of polysorbate 80–maltodextrin foams during microwave-assisted vacuum drying (MWVD) versus conventional vacuum drying (CVD). Aqueous dispersions of 3% polysorbate 80 and 0–40% maltodextrin were characterized for their dielectric and interfacial properties, and results were related to their drying performance in a foamed state. Surface tension and surface dilatational properties as well as dielectric properties clearly responded to the variation in the maltodextrin content. Likewise, the foam structure preservation during CVD was linked to the maltodextrin concentration. Regarding MWVD, however, foams collapsed at all conditions tested. Nevertheless, if the structure during MWVD remained stable, the drying time was significantly reduced. Eventually, this finding could be linked to the dielectric properties of polysorbate 80 rather than its adsorption kinetics and surface film viscoelasticity as its resonant frequency fell within the working frequency of the microwave drying plant.

scholarly journals Effects of sonication and freezing on the color, mechanical and thermophysical properties of osmo-microwave-vacuum dried cranberries

2020 ◽  
Author(s):  
Izabela Anna Staniszewska ◽  
Szymon Staszyński ◽  
Magdalena Zielińska
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Moisture Diffusion ◽  
Moisture Diffusivity ◽  
Microwave Drying ◽  
Vacuum Drying ◽  
Volumetric Heat Capacity ◽  
Drying Time ◽  
Microwave Vacuum Drying

The aim of study was to determine the effects of sonication (S), convective freezing (F), convective freezing preceded by sonication (SF) as well as cryogenic freezing (N) on the osmo-microwave-vacuum drying kinetics, energy usage and properties of dried cranberries such as moisture content, moisture diffusion, water activity, density, porosity, thermal conductivity, thermal diffusivity, volumetric heat capacity, lightness, redness, yellowness, total differences in color, saturation and hue, hardness, cohesiveness, springiness, and chewiness. Osmo-microwave-vacuum drying of cranberries took from 13.5 to 16.0 min. All initial treatments increased the moisture diffusivity and thus reduced the drying time. The most energy effective method was osmo-microwave-vacuum drying preceded by sonication (S) of fruits. Osmo-microwave-drying of cranberries subjected to convective freezing preceded by sonication (SF) resulted in the highest lightness (32.5 ± 0.5), redness (33.9 ± 0.7), and yellowness (11.3 ± 0.5) of fruits, as well as the lowest cohesion (the lowest resistant to stress associated with manufacturing, packaging, storage, and delivery). The lowest hardness, i.e. 12.3 ± 0.4 N and the highest cohesiveness and springiness, i.e. 0.38 ± 0.02 and 0.74 ± 0.03 of dried fruits, were noted for berries subjected to initial cryogenic freezing (N). Cryogenic freezing (N) combined with osmo-microwave-vacuum drying resulted in the largest color changes of fruits and the highest thermal conductivity. Sonicated and convectively frozen (SF) fruits were characterized by the highest thermal diffusivity. Sonication (S), convective freezing (F) and their combination (SF) significantly reduced the volumetric heat capacity of cranberry fruits.

Study of color kinetics of banana (Musa cavendish) under microwave drying by application of image analysis

2020 ◽  
pp. 108201322098133
Author(s):  
Sagar Nagvanshi ◽  
Subbarao Kotra Venkata ◽  
TK Goswami
Keyword(s):  
Microwave Power ◽  
Vision System ◽  
Power Level ◽  
Microwave Drying ◽  
Slice Thickness ◽  
Order Kinetic ◽  
Drying Time ◽  
Volumetric Heating ◽  
Kinetics Of ◽  
Microwave Power Level

Microwave drying works on the volumetric heating concept promoted by electromagnetic radiation at 0.915 or 2.450 GHz. In this study, banana ( Musa Cavendish) was taken as the sample and treated under microwave drying. The effect of two process variables, namely slice thickness (2, 3.5, and 5 mm) and microwave power (180 W, 360 W, and 540 W), were studied on drying kinetics and color kinetics. It was observed that the inverse variation relationship exists between drying time and microwave power level while drying time and slice thickness exhibited a direct variation relationship. A Computer Vision System (CVS) was developed to measure the color values of banana in CIELab space using an algorithm written in MATLAB software. Once the color parameters were obtained, they were fitted in First and Zero-order kinetic models. Both models were found to describe the color values adequately. This study concludes that microwave drying is a promising dehydration technique for banana drying that reduces the significant time of drying. Application of CVS is an excellent approach to measure the surface color of banana.

Optimization of the microwave drying process for potato chips based on the measurement of dielectric properties

2019 ◽  
Vol 37 (11) ◽  
pp. 1329-1339 ◽  
Author(s):  
GuiYi Luo ◽  
ChunFang Song ◽  
Pu Hongjie ◽  
Zhenfeng Li ◽  
Wanxiu Xu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Potato Chips ◽  
Microwave Drying ◽  
Drying Process

scholarly journals Comparative Study of Hot Air Drying and Microwave Drying for Dewatered Sludge

2021 ◽  
Author(s):  
Wittawat Wulyapash ◽  
Awassada Phongphiphat ◽  
Sirintornthep Towprayoon
Keyword(s):  
Microwave Power ◽  
Specific Energy Consumption ◽  
Microwave Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Dewatered Sludge ◽  
Dried Sludge ◽  
Seafood Processing

Abstract Large amounts of sludge are generated from wastewater treatment in seafood processing industries. Most of the dewatered sludge in Thailand is not utilized and disposed by landfilling. The dried sludge utilization as refuse-derived fuel (RDF) is an alternative solution due to the gross calorific value (GCV), which is greater than 21.9 MJ/kg. However, the key obstacle is its high moisture content of 87.4% (wet basis). Therefore, drying methods using hot air and microwave techniques were investigated for preparing dried sludge. The effects of hot air temperatures (100-150 °C) and microwave power levels (100-800 W) were compared on drying kinetics, specific energy consumption (SEC), and characteristics of the dried products. The results showed that drying times were decreased by increasing the hot air temperatures. In the same way, the increase in microwave power levels decreased the drying time. The application of microwaves contributed to reducing the drying time by more than 46% compared to the hot air. The reduction of drying times resulted in the saving SEC. The GCV of the dried sludge decreased with the decrease in the volatile matter (VM) due to the high component of VM as 79.5-80.3% (dry ash-free basis). The sludge dried by the microwaves showed a lower GCV than the hot air products. However, dried sludges still had high GCV (≥ 20.8 MJ/kg). Furthermore, the minimal variation of the product characteristics demonstrated that the microwave technique could be applied as an alternative drying method with a rapid process compared to the conventional hot air technique.

scholarly journals Application of sonication and freezing as initial treatments before microwave-vacuum drying of cranberries

2019 ◽  
Vol 2 (22) ◽  
pp. 151-167 ◽  
Author(s):  
Izabela Staniszewska ◽  
Szymon Staszyński ◽  
Magdalena Zielińska
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Physical Properties ◽  
Color Change ◽  
Vacuum Drying ◽  
Drying Time ◽  
Dried Fruits ◽  
Microwave Vacuum Drying ◽  
Drying Kinetic

The aim of study was to determine the influence of sonication and freezing on the kinetic of the microwave-vacuum drying, energy consumption and physical properties of whole cranberries as well as evaluate the applicability of sonication instead of freezing in order to change their physical properties and the drying kinetic of whole cranberries. Microwave-vacuum drying of whole cranberries with/without initial treatments took from 12 ± 1 to 14.5 ± 0.5 minutes. All of treatments did not significantly shorten the drying time of cranberries. However, they increased SMER values even by 31%. Despite of cryogenic freezing, all of treatments significantly increased the values of Dew. Sonication combined with drying allowed to obtain dried berries characterized by the lowest cohesiveness (0.19±0.02), springiness (0.62±0.02) and chewiness (3.4±0.8 N), while cryogenic freezing combined with drying allowed to obtain dried fruits characterized by highest springiness (0.75±0.03) and low chewiness (3.3±0.5 N). The highest lightness (32.2±0.7), redness (32.6±0.8), and yellowness (11.1±0.7) were found for fruits subjected to initial convective freezing before drying. The efficiency of sonication in color change was comparable to cryogenic freezing and much lower than convective freezing. All of initial treatments increased such thermal properties of dried cranberries as thermal conductivity and thermal diffusivity.

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